@larscom/ngx-translate-module-loader

Highly configurable and flexible translations loader for @ngx-translate/core. Fetch multiple translations (http only) and configure them to your needs. Each translation file has it's own namespace out of the box so the key/value pairs do not conflict with each other.

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Dependencies

@larscom/ngx-translate-module-loader depends on @ngx-translate/core and Angular.

Installation

npm install @larscom/ngx-translate-module-loader

Choose the version corresponding to your Angular version

Usage

Create an exported moduleHttpLoaderFactory function

import { NgModule } from '@angular/core'
import { BrowserModule } from '@angular/platform-browser'
import { HttpClientModule, HttpClient } from '@angular/common/http'
import { TranslateModule, TranslateLoader } from '@ngx-translate/core'
import { ModuleTranslateLoader, IModuleTranslationOptions } from '@larscom/ngx-translate-module-loader'
import { AppComponent } from './app'

export function moduleHttpLoaderFactory(http: HttpClient) {
  const baseTranslateUrl = './assets/i18n'

  const options: IModuleTranslationOptions = {
    modules: [
      // final url: ./assets/i18n/en.json
      { baseTranslateUrl },
      // final url: ./assets/i18n/feature1/en.json
      { baseTranslateUrl, moduleName: 'feature1' },
      // final url: ./assets/i18n/feature2/en.json
      { baseTranslateUrl, moduleName: 'feature2' }
    ]
  }

  return new ModuleTranslateLoader(http, options)
}

@NgModule({
  imports: [
    BrowserModule,
    HttpClientModule,
    TranslateModule.forRoot({
      loader: {
        provide: TranslateLoader,
        useFactory: moduleHttpLoaderFactory,
        deps: [HttpClient]
      }
    })
  ],
  bootstrap: [AppComponent]
})
export class AppModule {
  constructor(readonly translate: TranslateService) {
    translate.setDefaultLang('en')
  }
}

Namespacing

By default, each translation file gets it's own namespace based on the moduleName, what does it mean?

For example with these options:

export function moduleHttpLoaderFactory(http: HttpClient) {
  const baseTranslateUrl = './assets/i18n'

  const options: IModuleTranslationOptions = {
    modules: [
      // no moduleName/namespace
      { baseTranslateUrl },
      // namespace: FEATURE1
      { baseTranslateUrl, moduleName: 'feature1' },
      // namespace: FEATURE2
      { baseTranslateUrl, moduleName: 'feature2' }
    ]
  }
  return new ModuleTranslateLoader(http, options)
}

Lets say each module in the above example resolves to the following JSON:

{
  "KEY": "VALUE"
}

The final translation you are working with would be:

{
  "KEY": "VALUE",
  "FEATURE1": {
    "KEY": "VALUE"
  },
  "FEATURE2": {
    "KEY": "VALUE"
  }
}

Even though all JSON files from those modules are the same, they don't conflict because they are not on the same level after they get merged.

Configuration

The configuration is very flexible, you can even define custom templates for fetching translations.

interface IModuleTranslationOptions {
  /**
   * The translation module configurations
   */
  modules: IModuleTranslation[]
  /**
   * By default, each module gets its own namespace so it doesn't conflict with other modules
   */
  disableNamespace?: boolean
  /**
   * By default, namespaces are uppercase
   */
  lowercaseNamespace?: boolean
  /**
   * By default, it'll perform a deepmerge when merging translation files
   */
  deepMerge?: boolean
  /**
   * Set a version to prevent the browser from caching the translation files.
   * Each translation will get a query parameter with the version number
   * @example 'en.json?v=123'
   */
  version?: string | number
  /**
   * Function that gets executed if an error occurred while retrieving a translation file
   * @param error the error that occurred
   * @param path the path to the location file
   */
  translateError?: (error: any, path: string) => void
  /**
   * Custom translate merge function after retrieving all translation files
   * @param translations the resolved translation files
   */
  translateMerger?: (translations: Translation[]) => Translation
  /**
   * Provide custom headers at 'root' level, which means this headers gets added to every request
   * unless you specify headers at 'module' level.
   * @see modules
   */
  headers?: HttpHeaders
}

interface IModuleTranslation {
  /**
   * The module name
   *
   * For example: shared
   * @description omit moduleName if you have a translate file at baseTranslateUrl level
   * @see baseTranslateUrl
   */
  moduleName?: string
  /**
   * The base translate URL
   *
   * For example: ./assets/i18n
   * @description the final url will then be: ./assets/i18n/shared if the moduleName is shared
   * @see moduleName
   */
  baseTranslateUrl: string
  /**
   * By default, it uses the moduleName as namespace
   * @see moduleName
   *
   * Use this property if you want to override the default namespace
   */
  namespace?: string
  /**
   * Custom translation map function after retrieving a translation file
   * @param translation the resolved translation file
   */
  translateMap?: (translation: Translation) => Translation
  /**
   * Custom path template for fetching translations
   * @example
   * '{baseTranslateUrl}/{moduleName}/{language}'
   * or
   * @example
   * '{baseTranslateUrl}/{language}'
   *
   * It depends whether you have a moduleName defined
   * @see moduleName
   */
  pathTemplate?: string
  /**
   * Provide custom headers at 'module' level. These headers only apply to this module.
   */
  headers?: HttpHeaders
}

Custom templates for fetching translations

By default, translations gets fetched by using the following template:

'{baseTranslateUrl}/{moduleName}/{language}' e.g. ./assets/feature1/en.json

You can override this option if you wish to do so:

const options: IModuleTranslationOptions = {
  modules: [
    // resolves to: ./assets/my-path/en.json
    { baseTranslateUrl, pathTemplate: '{baseTranslateUrl}/my-path/{language}' },
    // resolves to: ./assets/my-path/en/feature1.json
    { baseTranslateUrl, moduleName: 'feature1', pathTemplate: '{baseTranslateUrl}/my-path/{language}/{moduleName}' },
    // resolves to: ./assets/my-path/en/feature2.json
    { baseTranslateUrl, moduleName: 'feature2', pathTemplate: '{baseTranslateUrl}/my-path/{language}/{moduleName}' }
  ]
}

Custom headers

  const options: IModuleTranslationOptions = {
    // global headers, applied to every request, unless you specify headers at 'module' level
    headers: new HttpHeaders().set('Header-Name', 'Header value')
    modules: [
      { baseTranslateUrl },
      // headers only applied to this module
      { baseTranslateUrl, moduleName: 'feature1', headers: new HttpHeaders().set('Header-Name', 'Header value') },
      { baseTranslateUrl, moduleName: 'feature2' }
    ]
  };